(1) Field of the Invention
The present invention relates to mass spectrometers and, more particularly, to the electronic drive and acquisition system for a mass spectrometer.
(2) Description of Related Art
Conventional drive systems for mass spectrometers are well known and have been in use for a number of years. Reference is made to the following exemplary U.S. Pat. No. 7,161,142 to Patterson et al., the entire disclosure of which is incorporated herein by reference. Regrettably, most prior art conventional drive systems for mass spectrometers suffer from obvious disadvantages in terms of mass-volume-power of the components and spectral resolution limitations. For example, as illustrated in the prior art FIG. 1, which is also illustrated in FIG. 10 of U.S. Pat. No. 7,161,142 to Patterson et al. (but without annotations), demonstrates a Full Width Half Max (FWHM) mass resolution M/ΔM of 92 AMU/2.25 AMU=40.9, which is a poor mass resolution by commercial standards. This poor resolution severely increases the mass cross talk, which precludes use of such a mass spectrometer for measuring accurate isotope ratios in, for example, nuclear treaty verification and in species age dating. In addition, as illustrated in the FIG. 9 of the same patent, the ramp waveform demonstrates non-linearity at the initial break point, which can lead to further degraded mass resolution near the Low Mass Cut Off (LMCO). Further, most prior art drive systems operate at a single frequency, and must be manually tuned (as disclosed in U.S. Pat. No. 7,161,142 to Patterson et al.).
Further, most components of the prior art mass spectrometer are three to ten times larger than the mass spectrometer sensor itself, and the output waveform developed from the existing drive electronics contains noise and harmonic distortion that continues to contribute to the sensitivity of the mass spectrometer. In particular, air-core transformers used in commercial systems to boost the amplitude of the mass spectrometer's RF driving voltage are one of the more bulky system components. The air-core transformers are part of an all-analog system that, when coupled to a high-Q inductor-capacitor resonance circuit, affords stable, high-amplitude RF voltage.
Accordingly, in light of the current state of the art and the drawbacks to current drive systems for mass spectrometers mentioned above, a need exists for an integral, miniaturized electronic drive and acquisition system for mass spectrometers that would have a small form factor in terms of mass and volume, and that would provide accurate, adjustable current and voltage drive and would further include an integral acquisition unit for acquiring and collecting final mass data in sync with the drive system. In addition, a need exists for an integral, miniaturized electronic drive and acquisition system for mass spectrometers that would exhibit highly stable and linear waveforms that would dramatically increase mass spectral resolution, and provide automatic self-tuning.